1. Field of the Invention
The present disclosure relates to medical devices and techniques for using medical devices and, more specifically but not exclusively, to an introducer for surgical airway catheters.
2. Description of the Related Art
This section introduces aspects that may help facilitate a better understanding of the invention. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art.
Emergency cricothyrotomy or tracheotomy can be performed using a traditional open technique (scalpel and tracheal hook), trochar type devices, or with a wire guided percutaneous approach using dilators (a.k.a. Seldinger technique). The preferred emergency surgical airway insertion site is the cricothyroid membrane because it is a relatively large space, it is devoid of large blood vessels, and it is generally accessible regardless of body habitus.
Open techniques involve a skin incision, stabilization of the trachea with either a tracheal hook or other instrument, and subsequent placement of a tracheal tube or surgical airway tube (tracheostomy tube or other short airway catheter) directly into the opening. These techniques are intimidating to providers without formal surgical training. Open techniques require fine motor control under situations of marked duress for operators and extreme time constraints for patients. Examples of these situations include hostile battlefield and tactical situations, in addition to traumatic presentations to emergency departments. Risks include vascular injury of laterally adjacent structures, perforation of the posterior trachea, creation of false subcutaneous passages, and fractures of the thyroid or cricoid cartilages due to the tracheal hook. Open surgical techniques are also technically challenging due to variations in the thickness of anterior neck tissues and bleeding that obscures landmarks. If control of the trachea by the tracheal hook is lost during the procedure, the opening may retract and be difficult to re identify.
Trochar type devices use sharp pointed blunt or hollow points to enter the skin and puncture the trachea, after which an airway tube is inserted (either over or through the sharp trochar). Upon insertion, the direction of force is in an anterior to posterior direction. This can cause compression of the trachea (decreasing the anterior posterior dimension) due to sudden and forceful entry into the trachea. The sharp point of such a device may then puncture the thin wall of the posterior trachea. This can result in procedural failure, false passage, mediastinal injury, subcutaneous emphysema, and tension pneumothorax. If the insertion point is off midline, then the great vessels of the neck (carotid artery and jugular vein) may be disrupted resulting in major bleeding. In many clinical situations that require surgical airway access, there is injury to the neck that may distort landmarks and proper identification of midline may be difficult.
Wire guided percutaneous devices are less intimidating to providers since a needle is used to place a wire into the trachea and no direct skin or tracheal incision is required. A skin or tissue plug in the needle may make identification of the trachea with a needle difficult or impossible. It is also possible to create a false passage with the wire. After the wire is placed, a dilator is used to serve as a stent for a cuffed short airway tube. To pass the dilator, the skin incision must be enlarged. Passage of the dilator and tube involves a relative sharp turn into the trachea. Expanding the skin incision requires cutting down on the wire using fine motor control of the scalpel while holding the wire in place. An inadequate skin incision, or an inappropriate insertion angle of the dilator and tube, may make passage into the trachea mechanically difficult. It can be difficult to control both dilator and tube during forceful insertion over the wire. The percutaneous method requires an average of 100 seconds before the patient can be ventilated. Since there is great reluctance for operators to initiate surgical airways, an additional 100 second delay to ventilation may result in hypoxic injury or death.